Bush maintained that the US needed to "take the fight to the enemy".
"Let the people of Iraq vote if they want the US to stay or leave"
Bob Kaye, Bohemia, US
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"To strike our country the terrorists only have to be right once. To protect our country we have to be right 100 per cent of the time," he said.
"That means the best way to protect our people is to take the fight to the enemy."
Tuesday's declassification came as the Democratic-led congress prepared to approve funding for the war, which polls show a majority of Americans oppose.
Bush wants nearly $100 bn to fund the wars in Iraq and Afghanistan.
The House of Representatives is expected to vote on Thursday, before sending the bill to the senate for final passage of the measure that will bring total war spending to more than $500 bn since late 2001.
Urging Americans to stay alert, Bush cited the newly-released information saying that al-Qaeda leader Osama bin Laden in 2005 ordered a cell to be set up in Iraq to plot attacks on US targets.
Further evidence was shown linking bin Laden to Abu Musab al-Zarqawi, the former head of Iraq's al-Qaeda wing who was killed in a US air strike in June 2006.
"The best way to protect our people is to take the fight to the enemy"
Bush said bin Laden had ordered al-Zarqawi in January 2005 to form a cell to conduct attacks outside of Iraq and to make the US his "number one priority".
"In the minds of al-Qaeda leaders, 9/11 was just a down payment on violence yet to come," Bush said in defence of his decision to send more troops to Iraq.
Since 9/11, he said, Americans have been "living in the eye of a storm" where dangerous swirling winds "could reach our shores at any moment".
Critics say Bush was trying to de-emphasise the role of sectarian fighting in Iraq and justify US military presence by focusing on ties to al-Qaeda and bin Laden.
The administration has also abandoned earlier charges tying al-Qaeda to Saddam Hussein, the Iraqi president, who was toppled in a 2003 US-led invasion.
Fran Townsend, Bush's homeland security adviser, said the intelligence on the al-Zarqawi-bin Laden connection was declassified because all leads had been exhausted.